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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

SCA-35 Dynaco

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Hi,

I see some nice condition SCA-35 on E-bay sometimes. Would that be a good place to start??

Basically I want a decent tube amp for a turn-table.

This would be my first foray into the world of tubes and wan't something reliable and functional.

any advice would be great- Thanks!!
 
Replace the electrolytic capacitors and the tubes. The coupling caps would also be something I'd go after. Don't use fashion parts, normal polypropylene caps (e.g., Wima MKP or 715P Orange Drops) will be fine in this circuit. Clean the switches and potentiometers with spray contact cleaner and some rotation. Then sit back and enjoy.

After you've got it refurbished and used it for a while, we can talk about upgrades.
 
SY said:
Replace the electrolytic capacitors and the tubes. The coupling caps would also be something I'd go after. Don't use fashion parts, normal polypropylene caps (e.g., Wima MKP or 715P Orange Drops) will be fine in this circuit. Clean the switches and potentiometers with spray contact cleaner and some rotation. Then sit back and enjoy.

After you've got it refurbished and used it for a while, we can talk about upgrades.


Hi Thanks,

Where would I find things like that??

Brian
 
Hi Thanks.

I love my records and music in general. Someone turned me on to the Lenco rebuilds and I thought that was cool so I got one of those and I'm working on the plinth.

I started thinking about Amps and had heard great things about tubes. So here I am!! Building a plinth I understand. Replacing capacitors not so much lol but with time comes knowledge

It is whole new world and kind of intimidating but it looks to be a great hobby and I look forward to learning as much as I can.

Brian
 
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Hi Brian,
SY is right on the money! I love good tube gear.

Understand that whatever you pick up is probably over 40 years old. It will need some rebuilding. Don't even bother turning it on until this is done. Bad things may happen if you do.

Sy is also right about part types, you want good parts and the normal ones are. Magic parts do not exist.

-Chris
 
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Hi Brian,
You will need to find something you like. At that power level you might be served well with speakers 90 dB per watt or above. The actual speaker you like is going to be hard for anyone to guess at. Expensive speakers will sound better to more people. Once you start going down in price it becomes more what tradeoffs you personally can deal with.

I'm sure SY may have some suggestions for you. Klipsch make decent sounding speakers and are efficient. There are many horn types out there also. A speaker design where you build the boxes and crossover would get you the best sound. Often because manufacturers do not build boxes the optimal size. Think shipping and weight. Now you know why.

-Chris
 
Hi,

Well I have no idea really. My brother had a pair of Bose 301 many years ago.

I'm just wondering if you guys know a certain type or manufacturer that would go with the Sca-35 system. I'd be happy to let you guys pick-em out considering I don't know anything.

$2oo to $400 range

I'll look at klipsh- thanks
 
bri2u2002 said:
...
I'm just wondering if you guys know a certain type or manufacturer that would go with the Sca-35 system....

Speakers are almost (or maybe even more?) personal a choice than amplifiers! :D Everyone will have some input re: efficiency, coloration, bass response, bass reflex vs. acoustic suspension vs. open baffle vs. horn etc. etc..

The choice also depends on the type of music you listen to, how loud you like to listen, the size of your listening room, etc. etc.. It is easy to get paralyzed by indecision trying to balance all the factors! :xeye:

So... How about a pair of Dynaco A25s? A good sounding 10 inch two way from the same company that made your amp. Not horribly efficient (I think about 90dB/W/1M?) so window shaking SPLs aren't likely with (an optimistic) 17.5WPC. I have a pair I have used with a 7 watt SET and unless I'm trying to shake the walls they work just fine. Usually on eBay for less than $200/pair.

Another very nice speaker in the 'budget' price range is the Advent/1 (yes I have a pair of those as well). These aren't the original 'Large Advents' but a later version. Also a 10" two way. A bit larger than the Dynaco A25. The Advents are acoustic suspension (no port) and are slightly less efficient than the A25s at about 87dB (IIRC). Again with non-ear-bleeding volume levels they will work with 17.5WPC. This model is rarer on eBay than the A25 but when available seem to go for $200-$250.
 
Hi! My current speakers are a pair of Altec Boleros, with which I am quite pleased. They are 10" with a 10 passive and a small hf horn. Altec didn't publish the efficiency rating on this system, but I'd guess it's in the range of 94-96 dB/w, as Altec (the original company, not the current "computer speaker" company), didn't build low efficiency speakers. These show up fairly regularly on eBay in the $200-400 range, although the price has been going up lately, as more people "catch on" to what these are. If you are interested, try for the "B" or "C" model, as the "A" has a horn that's unrepairable and nearly unreplaceable, except at a very high cost.
IMHO, I'd avoid "BOSE" speakers!
 
No, tubes plug into tube sockets. I'd suggest that you browse the internet for some basic electronics tutorials--there are a number of these available for free. I'd also suggest that you purchase and read a couple books on the same subject, before you do anything. Also read the permanently posted documentation on basic safety proceedures in electronics thats near the top of the list of posts, on the opening page.
 
I just noticed............. there is a post just below the above mentioned "Safety Practices........" , post, that references online materials for "Newbies". It points to a considerable number of good educational sources. Some, however, are for novices, while others are far more advanced. You really need to spend some time in both these posts. Good Luck! :)
 
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